The vacuum tube triode has been in existence for quite some time, and during that time many improvements have been made which resulted in the reduction of the size of triodes. Smaller triodes use less power and can be used in more applications. Thus, the miniaturization of triodes is a highly desirable goal. The state of the art in miniaturized triodes today are vacuum microelectronic triodes fabricated by VLSI integrated circuit and/or micro-machining techniques. Such techniques miniaturize triodes to the integrated circuit level but still leave room for further miniaturization. In applications such as with active antenna arrays for the H, I, and J frequency bands, device sizes ar required that are less than 0.5 inch square by 5.0 inches in length. These size requirements include the space dedicated to power conditioning components. The size requirements of these current and future antenna array systems tax traditional wide band component technology, proving the need for further miniaturization.
Prior art microelectronic triodes that operate up to 300 GHz use either a vertical scheme that places many triodes in parallel, or are deposited with a lateral topology utilizing strip line interconnects. Microelectronic triodes utilizing lateral topology are discussed in "Lateral Miniaturized Vacuum Devices", by H. H. Busta, J. E. Pogemiller and M. F. Roth, IEDM, 89-533, IEEE 1989. In triodes with a vertical topology, each cathode has a single field emitter tip. In such a vertical topology, the parallel outputs combine to increase the overall current available from the single field emitter tips of the cathode, by the number of triodes connected in parallel. In triodes utilizing a lateral topology, the individual triodes are joined with strip line interconnects. The strip line interconnects joining the triodes occupy a large portion of the space available in the triode array. Consequently, the power density within the triode array decreases. The lateral topology triodes also require an RF connection using external components in order to deliver the power to the intended load.
It is, therefore, a primary objective of the present invention to create a vacuum microelectronic triode having a lateral topology that creates a high power density and eliminates the need for RF connections, consequently allowing the triode to be further miniaturized.